[4] Sometimes separated as a distinct order under the name of Radiolaria.
[5] Loftusia Columbiana, Dawson, from British Columbia, is the only Carboniferous species yet known.
[6] See Nicholson in the Memoirs of the Palæontographical Society.
[7] Archæospherinæ of the author.
[8] Eophyton Linnæanum (Torrell).
[9] See Paper on “Footprints and Impressions of Animals,” Am. Journal of Science, 1873.
[10] They probably belong to a large sponge named by Billings Trichospongia sericea.
[11] Amphispongia.
[12] Geological Magazine, May, 1878.
[13] It is regarded as somewhat doubtful whether these are Hydroids or Bryozoa.